Fermi Surfaces of Surface States on Si(111)
Fermi Surfaces of Surface States on Si(111)
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DOI：
10.1103/physrevb.66.205302
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发表时间：
2002-05
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通讯作者：
J. Crain;K. N. Altmann;C. Bromberger;F. D. O. Physics;U. O. W. Madison;D. Physics;Philipps - University;Marburg;H Germany
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作者：
J. Crain;K. N. Altmann;C. Bromberger;F. D. O. Physics;U. O. W. Madison;D. Physics;Philipps - University;Marburg;H Germany
半导体衬底上的金属表面态提供了一个研究与体分离的低维电子的机会。角分解光发射用于确定$\mathrm{Si}(111)\sqrt{3}\ifmmode\倍\else\texttimes\fi{}\sqrt{3}\ensuremath{-}\mathrm{Ag}、$ $\mathrm{Si}(111)\sqrt{3}\ifmmode\倍\else\texttimes\fi{}\sqrt{3}\ensuremath{-}\mathrm{Au}、$ $和$\mathrm{Si}(111)\sqrt{21}\ifmmode\倍\else\texttimes\fi{}\sqrt{21}\ensuremath{-}（\mathrm{Ag}+\mathrm{Au}）表面态的费米面、群速度和有效质量。对于$\ mathm {Si}(111)\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}\ensuremath{-}\ mathm {Ag}$，费米表面由小的电子口袋组成，这些电子口袋由来自几个%的Ag的多余电子填充。对于$\mathrm{Si}(111)\sqrt{21}\ifmmode\times\else\texttimes\fi{}\sqrt{21}\ensuremath{-}(\mathrm{Ag}+\mathrm{Au})$，每填充一个单元格，口袋的大小就增加三个电子。$\sqrt{21}\ifmmode\乘以\else\texttimes\fi{}\sqrt{21}$超晶格导致了一个复杂的表面umklapp模式和110 meV的小缝隙，使得$\sqrt{21}\ifmmode\乘以\else\texttimes\fi{}\sqrt{21}$超晶格的相互作用电位为55 meV。
Metallic surface states on semiconducting substrates provide an opportunity to study low-dimensional electrons decoupled from the bulk. Angle resolved photoemission is used to determine the Fermi surface, group velocity, and effective mass for surface states on $\mathrm{Si}(111)\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}\ensuremath{-}\mathrm{Ag},$ $\mathrm{Si}(111)\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}\ensuremath{-}\mathrm{Au},$ and $\mathrm{Si}(111)\sqrt{21}\ifmmode\times\else\texttimes\fi{}\sqrt{21}\ensuremath{-}(\mathrm{Ag}+\mathrm{Au}).$ For $\mathrm{Si}(111)\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}\ensuremath{-}\mathrm{Ag}$ the Fermi surface consists of small electron pockets populated by electrons from a few % excess Ag. For $\mathrm{Si}(111)\sqrt{21}\ifmmode\times\else\texttimes\fi{}\sqrt{21}\ensuremath{-}(\mathrm{Ag}+\mathrm{Au})$ the pockets increase their size corresponding to a filling by three electrons per unit cell. The $\sqrt{21}\ifmmode\times\else\texttimes\fi{}\sqrt{21}$ superlattice leads to an intricate surface umklapp pattern and to minigaps of 110 meV, giving an interaction potential of 55 meV for the $\sqrt{21}\ifmmode\times\else\texttimes\fi{}\sqrt{21}$ superlattice.